Adjustable stroke eccentric mechanism



Nov. 30,4948. N. MICHELMANY 2,454,881-

ADJUSTABLE STROKE ECCENTRIC MECHANISM Filed Sept. 12, 1946 INVENTOR.

NATHAN MICHELMAN Patented Nov. 30, 1948 ADJUSTABLE STROKE ECCENTRIC' MECHANISM Nathan Michelman, New York, N. Y.

Application September 12, 1946, Serial No. 696,539

4 Claims. 1

This invention relates to an adjustable stroke eccentric mechanism for actuating reciprocating element or slide in a machine such as a press or the like. While reference is made herein particularly to presses wherein the stresses in the slide actuating mechanism are particularly high, it is to be understood that my invention can be applied to any other mechanism in which it may be desirable to vary th length of stroke of a reciprocating element.

According to my invention power is transmitted from a driving shaft to a slide through a connecting rod and a combination of eccentrics, said eccentrics having a free or slidable engagement with one another to vary their angular relationship, the outer one of said eccentrics being driven from said driving shaft through the interposition of suitable disengageable coupling means. As long as said coupling means are engaged, the combination of eccentrics behave as a single ccentric of a certain eccentricity. When said coupling means are disengaged, the angular relationship of the eccentrics can be manually varied to change the total eccentricity of the combination practically to any desired value comprised between zero and a maximum. Suitable scale means are preferably provided to indicate the total eccentricity.

It is the general purpose of my invention to provide an adjustable stroke eccentric mechanism for use in presses or the like, which mechanism may be set for practically any length of stroke between zero and the maximum.

A more specific object is to provide a mechanism of the character described, wherein the length of stroke may be set to the desired value in a single operation and without disassembling any part of the mechanism.

Another object is to provide a mechanism of the character described, wherein the length of stroke may be adjusted to a very fine degree, and wherein the available lengths of stroke are so close to each other that the adjustment is practically continuous and can be made truly continuous, if so desired.

A further object is to provide a mechanism achieving the previous object with an extreme simplicity and the ruggedness of structure and a minimum of component parts.

A still further object is to provide a mechanism of the character described, wherein the length of stroke may be adjusted in a single manual operation requiring the shortest time and needing no special skill on the operators part.

A still further object is to provide a mechanism achieving any and all of the aforementioned objects, which mechanism is efficient, simple and economical to manufacture.

Other related and ancillary objects of my invention will clearly appear as the description proceeds.

In the drawings:

Fig. 1 is aside view and part longitudinal section of a mechanism according to my invention.

Fig. 2 is a cross-section of Fig. 1 taken along the line 2-2 looking in the direction of the arrows, particularly showing the centers of the various component elements of the mechanism.

Fig. 3 is a cross section of Fig. 1 taken along the line 3-3, looking in the direction of the arrows.

Fig. 4 is a plan view of the mechanism of Fig. 1.

Fig. 5 is a plan view of a detail of the same mechanism shown in an inoperative or disengaged position.

Referring now in detail to the drawing, to designates a driving shaft, and II designates a connecting rod, of which only part is shown, which connecting rod is coupled to the slide, also not shown, and embodies an eccentric strap l2.

l3 are plates or in general stationary elementsv forming part of the frame of the press or like machine of which this mechanism is a part, in which frame the shaft I0 is supported.

An inner eccentric I4 is fast on the shaft 10 and may be solid therewith or rigidly connected thereto. Freelymounted on the inner eccentric I4 is an outer eccentric I5, which latter is provided with means for rotating it with respect to the inner eccentric. In the particular embodiment shown, thesemeans comprise holes It in the periphery of the eccentric IS, in whichv holes Hi there can be'inserted a rod or .keywhereby the eccentric l5 can be turned. However, any number of substantially equivalent mechanical means could be devised to substitute for the holes l6 and the corresponding key. On one end of the eccentric l5 there are formed or attached a num-: ber of longitudinally projecting teeth indicated at IT. These teeth are disposed on a circle concentric with the inner eccentric l4, so that no matter what the angular position of the outer As in the. case of theholes I6, suitable actuating means could be substituted for theholes 23 and the corresponding key. The member 22 has a number of pins 24, in the embodiment illustrated two of them, radially projecting internally .of. a sleeve portion of the member 22, which sleeve portion surrounds the hub portion I9 of the member I8.

Said cam slots 26 extend at an angle to the axis of the shaft I0, so that if the member 22 is rotated about the shaft Ill, the member I8 which cannot so. rotate is forced to move axially with respect to said shaft.

When the member I8 is all the way to the right, as viewed in Fig. 1, the teeth I! and the teeth.2l are in engagement. The member 18 rotates with the shaft I0, inasmuch as it is keyed thereto. Therefore the outer eccentric I5 must also rotate with. the shaft land with the inner eccentric I4 which is fast to this latter. The direction of the cam slots 26 is so related to the directionof rotation of the shaft ID that the effect of. said rotation is to urge the member I8 to the. right. Thus in operation there is no possibility that the teeth IT and El will become disengaged. Now if the member 22 is manually rotated in adirection to force the member I8 tothe left as viewed in Fig. 1 (the direction indicated by the arrow in Fig. a), said teeth. I! and 2i become disengaged the ones from the others. Now the out-er eccentric I5 is free. to rotate between the inner eccentric i4 and the eccentric I4 and the eccentric strap I2. As it rotates, the total eccentricity of the mechanism varies. It is desirable to have a scale marked on the periphery of the outer eccentric i5 and an index for. such scale in, invariable positioned relationship tothe inner eccentric It. Said scale preferably has indicatedth'ereon the length of. stroke corresponding to each angular position of the outer eccentric I5, so that the mechanism may be directly set by an operator to the desired length of stroke. When the outer eccentric I5 has been brought to the desired angular position, the member 22'is actuated in .a direction opposite to the. arrow of Fig. 4, the member I8 is urged all the way to the right, the teeth I! and'ZI become once more engaged, and the outer eccentric I5 is once again in driving connection with theshaft III. Obviously'in: the embodiment illustrated the angular position. of the outer eccentric I5 must. be one in which the teeth fl and 2| can be engaged, that is the angular displacements that are possible must produce peripheral displacements of the teeth I? equal to a multiple of the width of a tooth. This sets alower limit for the smallest permissible angular adjustment of the outer eccentric I5. However, said lower limit is small enough for any practical application. Still, if so desired, a clutch arrangement different from the one illustrated, could be provided in order to lower saidlower limit still further. It would even be possible. to employ a clutch of any one of the types which canbe engaged in any angular relationship. It isto be clearlyxunderstood that teeth I1 and 2I: have been shown a preferred means for: establishing a Said pins 24 engageacorresponding. number of cam slots 26 in the. hubportion. I9...

driving connection between the member I 8 keyed to the shaft I0 and the outer eccentric I5 solely for the sake of illustration, and that a person skilled in the art could devise any number of mechanical equivalents thereof without departing from the invention.

Fig. 2 has indicated thereon at A, B and C respectively the centers of the outer eccentric I5, the inner eccentric I4 and the driving shaft III. The eccentricity of the outer eccentric I5, which is also the total eccentricity of the mechanism is, by definition, the distance between the center A of the eccentric-figure and the center C of rotation.

In this further embodiment of the segment AB is equal to the segment BC. In the arrangement of. Fig. 2, wherein the points A, B and C are in a straight line, the length of stroke is maximum as the eccentricities of the two eccentrics are added to one another.

Indicating by r the length of segments AB or B0, if. the outer eccentric is rotated by an angle a one way or the other from the position of Fig. 2, the total eccentricity -is equal to 21'. cos

It is seen that the total eccentricity is equal 10.21, a maximum, when a=0, and becomes zero when a=l, that is when the outer eccentric I5 has been rotatedso that the center A coincides with the center C. Any value of thestroke between zero andthis maximum can be obtained by angular adjustments of the outer eccentric I5 in the manner hereinbefore described. If AB is not equal to B0,. the relationship between angle a and total eccentricity is slightly more complex, but still easily obtainable .by application of the law of sines.

While I have described a preferred embodiment of my invention by way of illustration, I want it understood that I am not to be limited to the details hereinset forth, and that many modifications and adaptations may be made in the mechanism described by persons skilled in the art without departing from the spirit of the invention or exceeding the scope of the appended claims.

I claim:

1. In aniadjustable stroke eccentric mechanism in combination with a reciprocating driver fora reciprocable member; a driving shaft, an inner eccentric fast on said shaft, an outer eccentric free on said inner eccentric, means for operatively connecting said outer eccentric to said driver for the reciprocable member, a member keyed to said driving shaft and actuable between two extreme positions, means for coupling said keyed member to said. outer eccentric to drive the latter, said coupling-means being operative when said keyed member is in one extremeposition and inoperative when said keyed member is in the other extreme position, a member free on said shaft, means for rotating said free member on said shaft, mutually engaging cam and follower means in said keyed member and free member for actuating said keyed member between said two extreme positions thereof in response to a rotation of said free member, and means for rotating said outer eccentric with respect to said inner eccen tric when said coupling means are inoperative, whereby to vary the eccentricity of said outer eccentric with respect to said driving shaft and to adjust the stroke of the reciprocable member.

2; In an adjustable stroke eccentric mechanism in combination with a reciprocating driver for a reciprocable member; a driving shaft, an outer eccentric free on said inner eccentric, means for operatively connecting said outer eccentric to said driver for the reciprocable member, a member keyed to said driving shaft and axially slidable between two extreme positions, means for coupling said keyed member to said outer eccentric to drive the latter when said keyed member is in one extreme position, said coupling means being inoperative when said keyed member is in the other extreme position, a member free on said shaft, means for rotating said free member, at least one follower pin fast to said free member, said keyed member having at least one slot engaged by said follower pin and disposed at an angle to the axis of said driving shaft, whereby rotation of said free member causes axial sliding of said keyed member between said extreme positions thereof, and means for rotating said outer eccentric with respect to said inner eccentric when said coupling means are inoperative, whereby to vary the eccentricity of said outer eccentric with respect to said driving shaft and to adjust the stroke of said reciprocable member.

3. In an adjustable stroke eccentric mechanism in combination with a reciprocating driver for a reciprocable member; a driving shaft, an inner eccentric fast on said shaft, an outer eccentric free on said inner eccentric, means for operatively connecting said outer eccentric to said driver for the reciprocable member, a member keyed to said driving shaft and actuable between two extreme positions, means for coupling said keyed member to said outer eccentric to drive the latter, said coupling means being operative when said keyed member is in one extreme position, a member free on said shaft, hand-actuated means for rotating said free member on said shaft, mutually engaging cam and follower means in said keyed member and free member for actuating said keyed member between said two extreme positions thereof in response to a rotation of said free member, and hand-actuated means for rotating said outer eccentric with respect to said inner eccentric when said coupling means are inoperative, whereby to vary the eccentricity of said outer Number eccentric with respect to said driving shaft and to adjust the stroke of the reciprocable member.

4. In an adjustable stroke eccentric mechanism, in combination with a reciprocating driver for a reciprocable member; a driving shaft, an outer eccentric free on said inner eccentric, means for operatively connecting said outer eccentric to said driver for thereciprocable member, a member keyed to said driving shaft and axially slidable between two extreme positions, a first set of teeth fast on said keyed member and disposed along a circle concentric with said inner eccentric, a second set of teeth fast on said outer eccentric and matable to said first set, said sets of teeth being in interlocking engagement with one another drivingly to connect said keyed member to said outer eccentric when said keyed member is in one extreme position and being disengaged when said keyed member is in the other extreme position, a member free on said driving shaft, means for rotating said free member, mutually engaging cam and follower means in said keyed member and free member for actuating said keyed member between said two extreme positions thereof in response to a rotation of said free member, and means for rotating said outer eccentric with respect to said inner eccentric when said sets of teeth are disengaged, whereby to vary the eccentricity of said outer eccentric with respect to said driving shaft and to adjust the stroke of the reciprocable member.

NATHAN MICHELMA'N.

REFERENCES CITED 'lihe following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Seymour Apr. 24, 1883 Hoaglund Jan. 19, 1926 Lubich Oct. 29, 1929 FOREIGN PATENTS Country Date Austria Apr. 24, 1883 France Sept. 29, 1941 Number 

